(1) Technical Field
The present invention relates to the field of wireless networks. More particularly, the present invention presents techniques for efficiently broadcasting information through a wireless network.
(2) Discussion
Growth in mobile wireless networks is fueled by the current increase in demand for telecommunication services. Cellular networks provide mobile users with the ability to be reached while in motion in defined coverage areas. Frequently, however, mobile users need to be able to communicate in situations where no fixed wired or wireless infrastructure is available, either because it may not be economically or physically feasible, or because the expediency of the situation does not permit installation. In such situations, a collection of mobile hosts may form a temporary network without the aid of any pre-established infrastructure or centralized administration. This type of wireless network is known in the art as an ad-hoc network. A node in such a network is a communicating entity, such as a mobile host or a sensor.
In very large network population situations, efficient resource handling requires that nodes be partitioned into teams. One of the principal actions of a mobile host is the dissemination of control messages to all other nodes in the team that share the same physical channel (frequency in FDMA, carrier and timeslot in TDMA, or code in CDMA systems). This procedure is known as Intra-Team Broadcasting. In mobile ad-hoc networks, control messaging is increased due to the inherent dynamic nature of the network. The lack of a central arbitrating agent also necessitates the existence of a robust and efficient packet broadcasting protocol. Control information about network status must be delivered in a timely and resource-efficient manner, so as not to prevent the channel from executing other protocols.
Presently, most control information broadcasting protocols, like classical radio communication networks, use flooding. In this approach, when a node receives a message, it relays it to all of its neighbors. Although flooding appears as the only reliable solution when the rate of topology change is high, it is not generally recommended in stationary or low mobility cases, as it results in intensive message circulation in the network. In such situations, additional bandwidth is consumed.
It is therefore desirable to develop an optimal broadcasting protocol for ad-hoc networks such that bandwidth consumption and maximum time delay are minimized. Several centralized or distributed methods for efficient, near-optimal, broadcasting in classical radio communication networks have been proposed and studied in the literature to date. Although some of these existing routing techniques can potentially be modified and used for broadcasting networks, simplicity and direct applicability are required to transmit control information reliably in broadcasting networks. Further, from the perspective of packet routing, it is desirable that such routing schemes be proactive, i.e., when a node is forwarding a message, the route should already be known and immediately applicable so that the forwarding delay is minimized